Precious metals, predominantly gold, are the bases for the principal alloys used in dental restorations. These alloys, although they serve the profession well, are costly. For continued effective use of these metals, it must be assured that the maximum performance is obtained per dollar of precious metal content and that as little as necessary of the precious metal be used to deliver the required performance. To achieve this objective it is proposed that a systematic study of gold-base alloys, specifically Au-Ag-Cu and Au-Ag-Pd, be carried out. Much of the metallurgical development of dental alloys took place in the 1930's. In the past 35 years new concepts relating structure and behavior of metals have evolved and new and more sophisticated experimental techniques for studying materials have been developed. These concepts and techniques will be focused on the strengthening mechanism and tarnish resistance of these alloys. Present alloys will be studied in order to establish an understanding of why they develop their useful properties. With this understanding it will be possible to explore modification of these alloys through composition and/or processing variations with a view towards obtaining satisfactory performance characteristics with a reduction of precious metal content. The program will involve dynamic interaction between researchers in the Metallurgy and Materials Science Department of the School of Engineering and Science and the Materials Research Laboratory of the College of Dentistry of New York University.